STL or 3MF: which file should I download?

The short answer

Print in one color? Download the STL. It works in every slicer.

Print in more than one color, or want the parts to arrive in your slicer already split up? Download the 3MF.

STL

An STL file is only a shape: a surface made of triangles. It has no colors, no units and no part names. Slicers assume millimeters, and every model on this site is made in millimeters, so the size is always right.

Because the whole model is one body, you can't give parts different colors without splitting it yourself in the slicer.

3MF

A 3MF file can hold several parts, each with its own name and color. Generators that offer "3MF · multi-color" put every colored part (for example the base and the raised text of a keychain) in the file as a separate part of one object, assigned to its own filament slot.

Bambu Studio and OrcaSlicer read the parts and their filament slots, so an AMS or other multi-material unit can print it straight away. Other slicers that support 3MF open the model too, but you may have to assign the filaments yourself.

Good to know

• Generated files are kept for a short time only. Download the file, don't bookmark the download link.
• To make the same model again later, use "Copy share link" on the tool page. The link stores all your settings.
• A 3MF is usually a bit larger than an STL of the same model, but both are small.